[PATCH v2 17/19] fbdev: Validate info->screen_{base,buffer} in fb_ops implementations

[Thomas Zimmermann]

Hi

Am 03.05.23 um 11:51 schrieb Geert Uytterhoeven:
> On Fri, Apr 28, 2023 at 2:26 PM Thomas Zimmermann <tzimmermann at suse.de> wrote:
>> Push the test for info->screen_base from fb_read() and fb_write() into
>> the implementations of struct fb_ops.{fb_read,fb_write}. In cases where
>> the driver operates on info->screen_buffer, test this field instead.
>>
>> While bothi fields, screen_base and screen_buffer, are stored in the
> 
> both
> 
>> same location, they refer to different address spaces. For correctness,
>> we want to test each field in exactly the code that uses it.
> 
> Not a direct comment for this patch: and later the union can be split
> in two separate fields, to protect against misuse?

No idea. Currently we have sparse that warns about mismatching address 
spaces if the fields are mixed up. That's good enough, as far I'm concerned.

Best regards
Thomas

> 
> Gr{oetje,eeting}s,
> 
>                          Geert
> 
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                  -- Linus Torvalds

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
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